Diagonal grading of shoes and lasts



July l1, 1950 Filed July 15, 1949- DIAGONAL GRADING 0F SHOES AND LASTS G. F. RYAN 2,514,518

l 2 Sheets-Sheet 2 fnvenor y @gorge F Ryan Patented July 11, 19,50

UNITED STATES PATENI" OFFICE 3 Claims." (Cl. 12F-1.46)"

This'inventionl relates to the manufacture of shoes fand, more particularly, to a method concerned with the manufacture of graded lasts for usein the making of shoes.

To' understand and appreciate better the nature of my kinvention a few preliminary remarks concerning certain conditions now obtaining in the last yand -shoemak'ing -art are pertinent. Custom-'- arily, shoes of any given style are individually manufactured in shoe factory units -called case 1ots.' These lots require vthe provision of one or more sets of corresponding lasts therefor. Now, for a givenstyle and Within'the different measurement ranges allotted to -mens, womensj and misses,'etc., a set of lasts normally includes a right and a left for each of the graduated size and width combinations, and it` becomes apparent that a very large number of lasts is required to enable a factory to manufacture a graduated run of shoes in several styles. Lasts accordingly represent 'af-considerable initial invesment and they usually must be replaced when damaged or outmoded.

Since hard wood such as rock maple, from which' the great majority of lasts preferably are turned, is becoming increasingly expensive, last construction of the two-part collapsible type is being more commonly employed. Each heel-part and fore-part can then be separately generated in a last lathe from a smaller rough block. Moreover, a heel-part or a 'fore-part may be replaced` when necessary without the need for replacing an entire last. In View of these circumstances and others, artisans suggest that lasts, 'and vespecially the less stylized heel-parts of lasts, be turned out of more dur-able and dimensonally stable materials than wood.v Also, it is recognized that when improving lthe functional 'role oflasts and lastparts vin'shoemaking further means should be sought by -w'hich-'to economize on whatever last materials are employed.

In general the term grading,- as -used in the f manufacture of lasts and patterns for shoemak` ing, refers to their pantographic generation from models.'V Thelength'y of the'graded lastisth'e'- dimension of the model parallel to its longitudinal` axis "-(the axis on which it is usually suspended inalast lathe), magnied'or reduced. Simi` larly, the width of the graded-last `maysbe'considered fto'be the magnified or reduced-radial dimension of themodel. measured from,xand` perpendicular to,` its longitudinal faxis.

Heretofore, `last 4makers are lbelieved to have* been'vunsuccessful @in 'making a :last-part l-accu-. rately lit lmore than-one `last `1 in 1a' :Jsystematicallyx Ting and, to some extent, shoemaking.

graded set ofvlasts. The idea has long vbeen entertained, however, that if interchangeability of lasteparts and shoe-parts'were feasible, suchy interchangeability would tend to simplify-last mak- While the substitution of certain shoe parts, such as counters, for ones which do not exactly match in size is sometimes indulged in, the resulting constructionvis not ordinarily tolerated in fine shoemakingf.4 Grading of shoes and the Whole lasts over which the shoes Were-made has almost invariably been in accordance with either of two plans, namely: (a) an arithmetic grading system whereinI lengths and widths are respectively enlargedr or diminishedin-equal increments,y or (lr)v a geometric grading system, as set forth in United f States Letters r Patent No. 1,948,547, granted on an application of L. E: Topham, under which length and width increments respectively increase or diminish in accordance with a xed percentage.' It is thisv latter, and relatively recent, development which' forms the preferred basis for practicing the novel method of last-part grading'h'ereinafterto be described although'it will be lunderstood "that" the invention can also be used 'with'arithmetic grading. Not the least of' the -advantages foreseenfor practicing the present method with respectfto the lheel-parts of lasts, for example, is Vthat heels and counters mayI the-@heel ends' of lasts of a graded setwhereby,

their interchangeability with corresponding parts iria "number off-lastsofthe set will be assured and attained without detriment to foot-fitting requirements or `style aspects of the set.

A further feature of the inventionis the'provisionofffa method` of gradingthe heel-lends of lasts' in asystematic set whereby their adaptability `with fore-parts of the set in lastv forming relation will be greatly increased.

Another feature ofthe inventionreside'sin the y provision `of a 'convenientmethod for identifying the heel-"parts of a set Which'are mutually inter- '55I changeabley endl-the -fore-parts with "which ff theinterchangeable heel-parts may be employed in last forming relation.

The above and other features of the invention together with valuable aspects thereof will now be further described and explained in connection with the accompanying drawings, in which Fig. 1 is a chart illustrating the diierent size and width combinations required in a graded set of lasts or individual last-parts for mens shoes;

in addition to representing a last or shoe, each consecutively numbered square may be considv ered to represent a diagonally graded heel-part of a last;

Fig. 2 is a diagrammatic view of heel-parts conveniently taken along their bottoms, but typical in accordance with this invention and exemplifying derivation of a portion of the chart of Fig. 1;

Fig. 3 illustrates the interchangeability of l a` and footwear are often used with different meanings. It may aid in avoiding confusion to consider that the following concepts for present pur-v poses hereinafter apply. Length and size, in-

dicated numerically, are interchangeable and pertain to longitudinal linear dimension of a last or shoe, or a part of a last or shoe. Girth and width, indicated alphabetically, are interchangeable and pertain, unless otherwise stated, to transverse circumferential dimension of a last or shoe, or of a part of a last or shoe.

The invention will be described with respect to the heel-parts of lasts although it will be understood other last-parts, and even shoe parts,

may be similarly treated. The invention is recognized as having special merit when applied to heel-parts since they are least subject to dimensional variation by reason of style factors and foot-ntting requirements- It will be seen from the consecutively numbered squares of Fig. 1 that at present there are required in the normal manufacture of a Single style of shoes for men approximately two hundred different lasts, including rights and lefts. U11- less it be quite by accident, no last or last-part is precisely interchangeable with any other in the set regardless of whether arithmetic or geometric grading be used. Each consecutively numbered square in the chart may be considered to represent a uniquely sized lastor last-part in the sel ries-` increments of length and/or Width (actually girth) being added systematically to progress from the smallest (-AA) which is not usually made in volume to the largest 13-E) which may not often be carried in stock. v v

If the lasts (Fig. 1) ybe graded systematically, each one bears a known but diiferent dimensional relation to another, Likewise, each heel-part, for example, of these approximately two hundred lasts is different and cannot at present be satisfactorily substituted for another heel-part in the l l series. To obtain interchangeability of heel-parts to the extent possiblewithout impairing the footl5 of any longitudinal section dimensionally related fitting requirements of shoes constructed from the graded set of lasts it is hereby proposed to grade up the heel end of a last of a given size, between successive widths, by adding length and girth increments respectively equal to the length and girth increments obtained from systematically grading to the next size larger than said given size. This next size, as is seen in Fig. 1, is numerically a half size greater than the given size.

To take an example under this method of grading, suppose a set comprises a geometrically graded last of size 9C, found in square No. B0 of the chart. By the method of this invention the heel l part for the 9C last (Figs. 1 and 2) may be geometrically graded as taught by the Topham patent cited to produce a 91/2C heel-part and, as seen by comparing the bottoms shown in Fig. 2, length and width or girth increments, respectively designated Zand g, have thus been added to produce a S31/2C heel-part having an over-all length L and girth G at its bottom.` The bottom views are preferred since they represent the insole pattern which is of prime importance to fit and to design.

Obviously G and L, or g and Z, may differ for other vlongitudinal sections of lasts in a set. The aim being to obtain interchangeability, the method provides that the heel-part for a 9D last of the set (found in square l1) is made or generated schematically from the 9C in the same way as the .9i/2C heel end. The 91/20 heel end may then be used in lieu of the 9D heel end, and vice versa: they are duplicates.

Pursuing the method of this instance further, the same heel-end, 91/2C or 9D, becomes interchangeable ywith lasts of the series having the length-girth combinations ill/2E, 10B, l0 1/2A, llAA. and these all fall along a diagonal of the chart of Fig. 1 (squares 93, 45, 29 and i3 respectively). Likewise the length-girth combi nations of heel-ends lying on other chart diagonals, such as that indicated lby squares 8,' 2d, 40, 56, 'l2 and 88, will .be interchangeable. Developing the idea more generally, themethod thus determines in this illustration that a single heel-end diagonally graded may be used on any one of six lasts, and, as may be determined from an inspection of Fig. l, diagonal grading of lastparts enables the usage of only 18 pairs of different heel-parts in lieu of the about 96 dilerent pairs of heel-parts that would have been required to satisfy this particular class of mens shoes.

To recapitulate, diagonal grading of the heelparts of lasts comprises grading the heel end ofv a last of a givenl size, between successive widths, byvalgebraically changing the length and girth, respectively, by increments equal to the increments obtained from length grading said given size. linterchangeability of heelfparts of lasts of a set and preserves uniformity and other benefits important to Shoemakng, it does not sacriiice the advantages to be derived from geometric grading when it is desired to employ this latter system. Thelasts required for the entire series may retain their over-al1 geometric proportions by suitably enlarging or diminishing the fore-parts as may be required by the individual diagonally graded heel-parts of a set.

YIncidental to the diagonal grading method disclosed, a convenient way for readily ascertaining the interchangeability 'of last-parts with others of a diagonally graded series is illustrated Iby the chart of Fig. l; AThe interchangeable last-parts all bear-the same identication num- While this method provides added ber. This number is easily determined in accordance with this formula: the identication number equals 2S+W, where S is the size of the last and W is the numerical value of the width, which ranges in whole numbers from for AA width to plus for E Width, as seen in Fig. 1.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of diagonally grading individual parts of multi-part lasts the complements of Which have been systematically graded from a primary model, which comprises grading the length and girth of the individual part of a last of a given size, between successive widths, by a1- gebraically changing the length and girth respectively by increments equal to the length and girth increments obtained from length grading said given size.

2. The method of diagonally grading the heelparts of lasts, the fore-parts of which have been geometrically graded from a primary model, comprising grading the length and girth of the heelend of a last of a given size, between successive Widths, by algebraically changing the length and girth respectively .by increments equal to the length and girth increments obtained from geometrically grading said given size.

3. The method of diagonally grading the heelparts of lasts, the fore-parts of which have been geometrically graded from a primary model, which comprises grading up the length and girth of the heel-end of a last of a given size, between successive widths, by adding length and girth increments respectively equal to the length and girth increments obtained from geometrically grading to the next size larger than said given size.

GEORGE F. RYAN.

No references cited. 

